The present invention disclosed herein relates to a touch panel, and more particularly, to a touch panel for providing a tactile feedback to a user according to an intensity of externally applied pressure.
Touch panels may be classified into resistive touch panels, capacitive touch panels, infrared touch panels, and ultrasonic touch panels according to operation principles. The resistive touch panels and the capacitive touch panels detect signals generated only by a touch. Therefore, these panels are not suitable for 3D displays that require proximity sensing. The infrared touch panels and the ultrasonic touch panels are not suitable to obtain a small size and implement a multi-touch function.
Recently, an optical waveguide-based touch sensor technology has been developed to overcome the above-mentioned limitations. The optical waveguide-based touch sensor technology enables miniaturization and provides a multi-touch function. Further, this technology enables a panel to have a film-type structure, and thus may be used for a flexible touch panel.
In particular, an optical waveguide-based touch panel using a pressure sensor has been developed. The touch panel using a pressure sensor may measure both a location and pressure and have a multi-touch function. However, this touch panel does not provide, to a user, a tactile feeling, i.e. a three-dimensional or haptic feeling, in response to an input. Therefore, various touch panel technologies for providing tactile feedback to a user are developed.